Typical methods for securing intellectual property involve using password-protected files. Such methods require the distribution and retention of a password to open the file. Passwords can be freely forwarded with the document to non-authorized users resulting in loss of intellectual property.
Steganography or “hidden writing” has been known for centuries. In ancient Greece, secret messages were tattooed onto the bald head of a courier who then grew out his hair to hide the message. When the courier reached his destination, he shaved his head to reveal the message on his bare scalp. In the middle ages, secret messages were encoded by objects in plain view such as flower arrangements, notes on a page of music, stars drawn onto a map, or the directions heads faced in a group portrait. In more recent times, microdots pasted as a “period” on a page of newsprint were used to carry secret messages.